The five year plan

[cs]

Of course here I go again thinking ahead. This time though I'm thinking into the five year plan. All this pre-planning helps me make a good decission when the time actually comes.

What I'm thinking about is when I start my Friendship. It is designed as a carvel planked boat with steam bent frames. What I plan on doing is converting from carvel to strip. I'll figure out the frame spaceing and plank thickness later. What I'm thinking about now is construction technique. I'll kinda outline what I'm thinking and you correct or fill in the blanks as I go.

What I'm thinking is that I'll make a plywood form for every frame and attach these forms (or molds) to the keel. I will than take my steamed frames and screw them to the forms from the side. Once all the frames are attached to the forms and they keel I can start stripping from the sheer to the keel, or should I start from the keel and work toward the sheer? Once the boat is stripped out I can than go in and remove the forms from the frames.

Does this sound like the best way? Should I build upside down or right side up?

Chad

[B_B]

Heard of someone doing this - and from their experience please ensure that the steam bent frames and plywood molds are easily separated after the planking :eek:

[Matt Middleton]

Hey Chad- I can't speak to the efficiency of this method, but the pictures are nice and will give you a starting point.

Hesp strip planking pages (http://members.aol.com/stripplanking/strip_planking/index.html)

Matt

[James R]

From personal experience I can tell you that building upside down is better when it comes to strip planking. The strips are usually too spindly to try to work with overhead when building right side up. Let gravity help you.

As for where to start planking, it's easier to start at the sheer and work your way up, but that doesn't mean that you should follow the sheer line with the first strip. By the time you reach the centreline the runout could be too severe. Measure the girth at the bow, amidships, and at the stern to figure out how much runout you'll have and go from there. You might even decide to use a few tapered planks somewhere if the curvature is too severe.

When it comes to the frames, I wouldn't attach them to the temporary forms, assuming that the forms are enough to define the shape of the hull. Let the frames float freely and attach them to the planking as you go along.

[cs]

Matt I'm printing that one out and will save and review.

James if you leave the frames free floating what do you do about forming them? I mean if they need to be steamed to be bent what do you do? I was thinking of attaching them to the frames to help hold their shape while stripping.

Yes, I guess paticular attention would need to paid to making sure form didn't get glued to the strips and frames. Maybe heavy grade plastic or duct tape.

Chad

[John Bell]

Why plywood forms? It seems to me (having never done something like this myself) that it wouldn't save anything over wooden forms and rib bands. You'll still have to put some wood on the edges of the ply to attach something to it, even if only temporarily. And what if you had to work inside the boat? All those walls in the way might be a problem.

That's my thought process anyway.

[James R]

James if you leave the frames free floating what do you do about forming them? I mean if they need to be steamed to be bent what do you do? I was thinking of attaching them to the frames to help hold their shape while stripping.You could pre-bend the frames on the lofting floor or attach temporary heavy stringers to the permanent and temporary bulkheads and shape the frames to those. You would then remove the stringers as you planked up to each one. My suggestion was because I had visions of all those screw holes, temporarily holding the frames, weakening them. You could also consider laminated frames. They would be larger but there would be fewer of them.

BTW, particle board is much better for temporary bulkheads.

[James R]

Chad, if you haven't done so already go and take a look at the third illustration from the top at Setting Up Frames & Planking (http://members.aol.com/stripplanking/strip_planking/html/setting_up_frames___planking.html). The frames will hold their shape because the floors, the sole supports, and in some cases, partial bulkheads are already attached. The frames are also longer than they need to be at the sheer. That extra length will be cut off later so that any holes from fasteners used to attach them to the strongback won't affect their strength. I suppose any extra bracing needed could be googed on. You could cut this bracing out later and grind or plane the googe.

[JimD]

Your plan sounds about right, Chad. Amigo is strip planked about the same way. Some of the frames are glued and screwed permanently to interior bulkheads that will remain in place, other frames are temporarily held in place on throwaway station molds until the strips go on. Afterwards the temp stations are removed.

[imported_Mac]

All,

I like this thread :D :D ; I am building one of John Hesp's desings.

Actually it is "Hope" as shown on his pages, but I've opted for the Bermudan rig. Also I asked John to redraw the hull so as we have a version with 1,30 m ( 4,3 ft) depth and no daggerboard.

I started this year, and I have 6 (out of 15) frames done, but fall has stopped me now :(

[cs]

Jim I read and printed out that whole thing and will file that away. When I get ready to start on the frames that looks like a good way.

Chad

[Doug Hamilton]

CS Two concerns:
1-For a counter-argument to Hesp as to the merits of strip-planking see www.gartsideboats.com/faq2.php#strip (http://www.gartsideboats.com/faq2.php#strip) .
2-Between 1920 and 1940, pinch-dogs were used to hold frames in place against inverted moulds at spacings of 9" to 18" while planking dinghies. Read pages 4 and 18 & 19 of the monograph written by Barry Thomas with Maynard Bray, "Building the Herreshoff Dinghy, the Manufacturer's Method".

[cs]

Okay after some thought I like the method shown at the link that Matt provided. Now to move on to the next issue.

Since this was designed as carvel and plan on doing it in strip, by theroy I could reduce the number of steam bent frames. But if I laminate the frames I need to increase the size of the frames. Well what if I keep the same number of frames and keep the same size and laminate them and strip the hull.

So what I end up with is the same size & quanity of frames but laminated instead of bent. This way maybe I make up for the weaker laminated frames. Does this sound like it will work?

Doug I looked at his points and will consider his thoughts.

Chad

[NormMessinger]

For what it is worth: If I were doing Prairie Islander again knowing what I know now I would laminate the frames on the mold and attache the floors prior to putting on the strips much as JamesR suggests above.

Are steam bent frames stronger than laminated frames? The later seem less trouble to make.

[L.W. Baxter]

That's kind of a surprising sentiment, Norm. Laminated frames less trouble than steam bent? Seems like, if you have access to the right kind of wood, steambending should go way quicker. This is just a guess, as I've only steam bent a grand total of two pieces of wood in my life. But it was surprisingly quick, (not counting the steaming time), and no trouble at all, really.

I guess it depends somewhat on your attitude towards goop. I use it, but I wouldn't mind using less!

By the way, Chad, I hope you have better luck with your "Five Year Plan" than Chairman Mao had with his!

[ 11-03-2003, 07:45 PM: Message edited by: L.W. Baxter ]

[NormMessinger]

"...if you have access to the right kind of wood..."

Well, that's part of the problem, isn't it? I would only attempt to defend my assertion based only on my own situation but if one is set up to saw and glue assembling steam bending stuff seems extra. I steam bent a couple of dozen 1/2" X 3/8" ash ribs for a little canoe. That does not count the broken ones, obviously not the right kind of wood. It seems to me one needs more than mickey mouse steaming gear to bend 2" x 1-1/2" x 4' ribs as in Prairie Islander.

But the question is not which is easier (to each her or his own) but is one stronger than the other?

[L.W. Baxter]

Part of the genius of Henry Ford was his realization that there's no point building any part stronger or more durable than it needs to be. On the perfectly engineered automobile, every part would fail at the same time!

What I mean is, laminated frames are more stable and probably stronger, but if bent frames do the job, and you can bend them faster (and quite possibly more cheaply), then it makes sense to use them. So, IMHO, strength is not neccessarily the bottom line.

[ 11-03-2003, 09:48 PM: Message edited by: L.W. Baxter ]

[NormMessinger]

Yes. I agree with that. Given the right material.

Okay, Chad, you can have your thread back now.